Spinal muscular atrophy

Diagnosis

Tests can be carried out to check if you or your child has spinal muscular atrophy (SMA), or if you're at risk of having a child with the condition.

Tests before getting pregnant

Speak to your GP if you're planning a pregnancy and:

  • you've had a child with SMA before
  • you have a history of the condition in your family
  • your partner has a history of the condition in their family

Your GP may refer you for genetic counselling to help you understand the risk of your child having SMA. You can have a blood test to see if you have the faulty gene linked to the condition.

If you're at risk of having a child with SMA, talk to your genetic counsellor about your options.

These may include:

  • getting pregnant and waiting to see if your child is born with SMA, or having tests during pregnancy to see if they will have it
  • using donated sperm or eggs to get pregnant
  • pre-implantation genetic diagnosis (PGD) – where a woman's eggs are fertilised in a laboratory and the resulting embryos are tested for SMA before being put in the womb

Tests during pregnancy

If you're pregnant and there's a risk you could have a child with SMA, tests can be carried out to check for the condition.

The two main tests are:

  • chorionic villus sampling (CVS) – a sample of cells from the placenta are tested, usually during weeks 11 and 14 of pregnancy
  • amniocentesis – a sample of amniotic fluid is tested, usually during weeks 15-20 of pregnancy

Both these tests can slightly increase your chances of a miscarriage.

If tests show your baby is likely to have SMA, talk to your doctor about what this means and what your options are.

Tests after birth

If you or your child has typical symptoms of SMA, a genetic blood test can be done to confirm the condition.

You may also be asked if anyone in your family has a condition that affect the nerves and muscles in your family.

A physical examination may be done to look for signs of SMA or similar conditions.

Very occasionally, other tests may be needed, too. For example:

  • electromyography – thin needles are inserted into a muscle to detect how well it's working
  • muscle biopsy – a small sample of muscle is taken for analysis
Page last reviewed: 12/06/2017
Next review due: 12/06/2020